C24NE rebuild advice

[2400man]

Evening Folks,

I’m finally getting a bit of spare time to rebuild the C24NE.

One query and excuse my ignorance but do I torque up the main bearing cap bolts, big end cap bolts, head bolts etc with the threads dry or oiled? The Haynes book of lies makes no mention, nor does Autodata. My machine shop says use the tiniest amount of light oil, just enough to stop the threads binding. What do you guys recommend?

TIA David

[Paul Barrett]

I’d go with Machine shop advice there. Won’t do any harm. 

Clean the threads out too thoroughly which I’m sure you already know. 

[Jessopia74]

Exactly as Paul described 👍

[GTEPETE]

I also run a clean up tap through all threads, and clean with brake cleaner...you will find it torques up nicely afterwards....

[2400man]

Thanks for the extra advice fellas. Just gotta warm up my torque wrench now 🙂

[GTEPETE]

As for head bolts, I use 2.2 bolts as are non-stretch 12.9 grade...and can be re-used...

[Jessopia74]

Where you buy your new parts from btw? 

[2400man]

10 hours ago, GTEPETE said:

As for head bolts, I use 2.2 bolts as are non-stretch 12.9 grade...and can be re-used...

That's interesting Pete. So 2.2 bolts are different from 2.4 type? I bought Victor Reinz bolts, can't remember where from, might have been Amazon....   I see that Edelschmiede stock them too. I've got to put an order in to Edelschmiede soon for gaskets etc

7 hours ago, Jessopia74 said:

Where you buy your new parts from btw? 

I'm just trying to remember Jess. I know it seemed to take forever to track down the standard sized bearing shells at the start of 2021 I think it was, because everywhere was out of stock and there was a delay with Glyco making more of them. I'll have to check back through my receipts.... 

[GTEPETE]

8 hours ago, 2400man said:

That's interesting Pete. So 2.2 bolts are different from 2.4 type? I bought Victor Reinz bolts, can't remember where from, might have been Amazon....   I see that Edelschmiede stock them too. I've got to put an order in to Edelschmiede soon for gaskets etc

I'm just trying to remember Jess. I know it seemed to take forever to track down the standard sized bearing shells at the start of 2021 I think it was, because everywhere was out of stock and there was a delay with Glyco making more of them. I'll have to check back through my receipts.... 

Is was more for info, Victor Reinz bolts are a good product...

[2400man]

22 hours ago, 2400man said:

That's interesting Pete. So 2.2 bolts are different from 2.4 type? I bought Victor Reinz bolts, can't remember where from, might have been Amazon....   I see that Edelschmiede stock them too. I've got to put an order in to Edelschmiede soon for gaskets etc

I'm just trying to remember Jess. I know it seemed to take forever to track down the standard sized bearing shells at the start of 2021 I think it was, because everywhere was out of stock and there was a delay with Glyco making more of them. I'll have to check back through my receipts.... 

Have checked back through receipts:

Elring green valve stem seals - worldcarparts.co.uk

Elring head gasket - GL Automotive, Nuneaton

Glyco std size main bearings - www.cs-parts.de

Stainless core plugs - www.coreplugs.co.uk

Crankshaft seals and std size big end bearings - alvadi.ee

[Jessopia74]

1 hour ago, 2400man said:

Have checked back through receipts:

Elring green valve stem seals - worldcarparts.co.uk

Elring head gasket - GL Automotive, Nuneaton

Glyco std size main bearings - www.cs-parts.de

Stainless core plugs - www.coreplugs.co.uk

Crankshaft seals and std size big end bearings - alvadi.ee

Always good to keep up with who has what mate, thanks

[GTEPETE]

Re www.coreplugs.co.uk, do they supply a full set for a 2.4, or you had to measure each  and order individually?

[H-400]

Hi David, succes with the rebuild of your 2.4. Got also a 2.4 in my GSI, must be yet a 2.5 cause I fitted an oversize of pistons 😁. I would advice what your machine shop says; use some oil. I'v got an original Opel workshop manual and they write do use engine oil on the bolts of main caps and big ends.  

About the 2.4: Those engines have the habit  to tumble their pistons cause of the longer stroke. I bought my 2.4 new in the box in 1993, naked bottom engine. Used this engine in several Manta's for years but never counted the mileage, must be more than 150.000km's. So a few years ago I had a rather strange noise in my engine and measured the bore of my cilinders and yes I had this problem. New oversize pistons and complete overhaul.  So if you open your engine measure the inside of your cilinders to be sure.   The flywheel: the bolts of the flywheel are not the same as classic CIH's. They have another thread, and as we are talking about those bolts: Beware of the "P"bolt. As GTEPETE wrote above: I use also those "older" head bolts:

Those old type of headbolts need the 12-star key, the more recent "one use stretch bolts" have the allan key.  I use those old type of bolts several times and never had problems with them. But they must be torqued in another way as the stretch ones, and retorqued after 1000Km's... If you want more info no problem.  The head of your engine: Is this an original 2.4 head? So yes you will need to check what kind of feul system you want to use. The original 2.4 head has got other inlet ports (higher) as a classic CIH. 

 

[cam.in.head]

this is where a little confusion also pops up on my part. sorry to jump in !

i have always reused the original early style splined bolts with no problems and done the retorque after 500ml. all as agreed above .but i cant remember where (or if !) i read somewhere many years ago that the later allen headed type were single use stretch bolts .its mentioned above (unless ive read it wrong) that they are marked 12.9 hence a normal reuseable bolt too ?

i must admit that i have reused these type of bolts anyway in both my 2.2 engines and never actually looked wether they were marked 12.9 or not ? ? 

[611]

These guys are good for CIH stuff and have most stuff in stock usually

https://www.krause-rennsporttechnik.de/shop/Motorenbereich/CIH

and Opel GT Source in the US are usually pretty good for 2.4 stuff

and https://enem.se/ib.asp do a nice cam for the 2.4 🙂

Used the stretch bolts on mine when i did the rebuild.

The was also an interesting discussion on the opelgt.com (If the link still exists you can see it in the image) about cylinders 3 & 4 getting hotter on the 2.4 and they recommended opening up extra waterways in the head gasket to keep them cooler.

Did it when i rebuilt mine.

 

 

Edited September 8, 2023 by 611

[GTEPETE]

HD FLYWHEEL BOLTS

Believe these are the correct ones, for 2.4 crank, Herman am I correct 10mm x 1.25mm by 25mm long. They are effectively 6 x P bolts.

https://www.ojperformance.com/shop/fasteners/drivetrain-fasteners-2/flexplate-and-flywheel/arp-flywheel-bolt-kit-10-mm-x-1-25-thread-1-000-in-long-12-point-head-chromoly-black-oxide-toyota-4-cylinder-set-of-8/

[2400man]

On 08/09/2023 at 02:31, GTEPETE said:

Re www.coreplugs.co.uk, do they supply a full set for a 2.4, or you had to measure each  and order individually?

I had to measure them individually and the guy at core plugs was struggling a bit with one of the sizes which was unusual. Haven't fitted them yet so will have to let you know how I get on.

On 07/09/2023 at 23:49, Jessopia74 said:

Always good to keep up with who has what mate, thanks

There's some other bits too, like the head bolts and piston rings....when I can find the details

Edited September 9, 2023 by 2400man

[H-400]

1 hour ago, GTEPETE said:

Believe these are the correct ones, for 2.4 crank, Herman am I correct 10mm x 1.25mm by 25mm long. They are effectively 6 x P bolts.

Thanks for the info Pete, think I never wrote down what size the thread was 👍

[2400man]

17 hours ago, H-400 said:

Hi David, succes with the rebuild of your 2.4. Got also a 2.4 in my GSI, must be yet a 2.5 cause I fitted an oversize of pistons 😁. I would advice what your machine shop says; use some oil. I'v got an original Opel workshop manual and they write do use engine oil on the bolts of main caps and big ends.  

About the 2.4: Those engines have the habit  to tumble their pistons cause of the longer stroke. I bought my 2.4 new in the box in 1993, naked bottom engine. Used this engine in several Manta's for years but never counted the mileage, must be more than 150.000km's. So a few years ago I had a rather strange noise in my engine and measured the bore of my cilinders and yes I had this problem. New oversize pistons and complete overhaul.  So if you open your engine measure the inside of your cilinders to be sure.   The flywheel: the bolts of the flywheel are not the same as classic CIH's. They have another thread, and as we are talking about those bolts: Beware of the "P"bolt. As GTEPETE wrote above: I use also those "older" head bolts:

Those old type of headbolts need the 12-star key, the more recent "one use stretch bolts" have the allan key.  I use those old type of bolts several times and never had problems with them. But they must be torqued in another way as the stretch ones, and retorqued after 1000Km's... If you want more info no problem.  The head of your engine: Is this an original 2.4 head? So yes you will need to check what kind of feul system you want to use. The original 2.4 head has got other inlet ports (higher) as a classic CIH. 

 

Thanks for your advice Herman. Re the tendency for the bores to ovalise on the 2.4 due to the longer stroke, yes I had this checked out by the machine shop last year after Andy Clears alerted me. Thankfully it wasn't an issue with mine and all that the shop advised was to do a re hone on the bores, which had some very light surface corrosion, and also to fit new piston rings.

Incidentally, my 2.4 is of somewhat unknown history. I bought it in 1995 from a company in Luton who sold it as an ex test bench engine from Vauxhall. It came with what looked like non-standard solid steel engine mounting brackets so I have always assumed it had never been in a vehicle and was as described. I completely dismantled the engine back then to check it over, and had porting work and combustion chamber work done on the head by Bill Blydenstein (RIP Bill) and he said the valve guides were worn and he used a knurling technique to tighted up the tolerances. It wasn't a very robust fix though and measurements I took in 2021 showed the clearances were out of spec. They also showed that the valve stems were fractionally thinner than the specs I have, which I got from Vauxhall in the 90's - maybe a sign of it being a development engine? Anyways, I had bronze valve guide inserts (Alfa Romeo) fitted in 2021 as part of this rebuild. 

Useful to know about the flywheel bolts having a different thread from other CIH's. Is it recommended to change these?

Re the head bolts, useful to know about the difference between the older 12-star key and the newer ones like I have. Can you still get the 12 point ones?

Re the fuel system, back in the 90's I attempted to use a cut down straight 6 inlet manifold with modified LE jetronic but I had bonnet clearance issues with the manifold and never got the injection running properly. So this time the plan is to have another bash with the inlet manifold and I have a spare straight six manifold that was obviously from an engine bay fire if I need to modify that. Re the fuel system, I got the engine running on the OE M1.5 motronic ages ago with the standard 2.4 manifold. Now after I get it running with the standard manifold etc, I want to remap the ECU to optimise it to run with the modified cut down straight six manifold / gas flowed head etc. I fully expect to have to run higher flow injectors and maybe a recalibrated 2.4 airflow meter. Could be fun sorting it all out 😁

14 hours ago, 611 said:

These guys are good for CIH stuff and have most stuff in stock usually

https://www.krause-rennsporttechnik.de/shop/Motorenbereich/CIH

and Opel GT Source in the US are usually pretty good for 2.4 stuff

and https://enem.se/ib.asp do a nice cam for the 2.4 🙂

Used the stretch bolts on mine when i did the rebuild.

The was also an interesting discussion on the opelgt.com (If the link still exists you can see it in the image) about cylinders 3 & 4 getting hotter on the 2.4 and they recommended opening up extra waterways in the head gasket to keep them cooler.

Did it when i rebuilt mine.

 

 

That's really useful stuff to know about the head gasket mod etc Andy 👍

17 hours ago, cam.in.head said:

this is where a little confusion also pops up on my part. sorry to jump in !

i have always reused the original early style splined bolts with no problems and done the retorque after 500ml. all as agreed above .but i cant remember where (or if !) i read somewhere many years ago that the later allen headed type were single use stretch bolts .its mentioned above (unless ive read it wrong) that they are marked 12.9 hence a normal reuseable bolt too ?

i must admit that i have reused these type of bolts anyway in both my 2.2 engines and never actually looked wether they were marked 12.9 or not ? ? 

I'll have to check my old head bolts and the V Reinz ones to see if any markings......

[GTEPETE]

One of my 2.4 Flywheel bolts was bent when removed. So replacing with ARP's ..As there are only 6 bolts, I have also fitted a stainless steel dowel, to locate the flywheel to crank, luckily there are already 2 drilled blind holes between the bolt holes in the end of the crank...recommended for high power CIH engines ...

[Paul Barrett]

28 minutes ago, GTEPETE said:

One of my 2.4 Flywheel bolts was bent when removed. So replacing with ARP's ..As there are only 6 bolts, I have also fitted a stainless steel dowel, to locate the flywheel to crank, luckily there are already 2 drilled blind holes between the bolt holes in the end of the crank...recommended for high power CIH engines ...

Will be doing this on my 2.4 16v

[H-400]

@David: When I gave my engine to the motor shop to bore and hone to the next size I asked them to drill a hole for the dipstick behind the engine mount at the same angle and diameter. If you are going to fit a steel sump I can mail you a template for an oil baffle plate, bought it once from Risse Motorsport and copied it on paper. 

This offer is ofcourse for everybody on this forum. 

I fitted a flywheel of a six cilinder CIH with the standard 2.4 bolts and a 9 inch clutch as my "400". Noticed a standard G/TE 8.5 clutch couldn't handle the torque. To compensate the lack of feul I fitted a feul pressure regulator of a L-jetronic. Gives 3bar while a LE just 2,5bar. The inlet manifold of a 2.4 fits normally under the hood of a Manta, but I have a 6 in line cut off manifold ready to install with 70mm throttle and BMW air flow meter.  Not sure those 12 star bolts of the older CIH's are stil available. They were used on all older CIH as also the 1.6 and 1.9 so Mr Carlos on this forum can help you?

[GTEPETE]

Herman, do you have a photo of the BMW throttle body. To see how it looks compared to the Senator 3.0 one?

[611]

7 hours ago, Paul Barrett said:

Will be doing this on my 2.4 16v

@Paul Barrett Fit a proper clutch!! https://www.theopelproject.com/fitting-the-mighty-s10-clutch/

@2400man Use the ARP bolts, that 2.4 will have a fair bit more torque compared to most CIH engines so you want to make sure anything between the engine and box can handle it.

Some info on my blog for a few bits i have fitted to mine 🙂

https://www.theopelproject.com/

Andy

[Jessopia74]

That S10 clutch is exactly what I have gone with mate, followed your advice. Obviously still a little way to go, but one less thing to ‘find a solution for 🍻👍